Primary

More ways exercise can help seniors fight memory loss

September, 2011

A recent study finds that cognitive decline is greater in older adults who have a high salt intake —but only if they’re not physically active. Another finds that older rats who exercise are protected from memory loss caused by bacterial infection.

A three-year study following 1,262 healthy older Canadians (aged 67-84) has found that, among those who exercised little, those who had high-salt diets showed significantly greater cognitive decline. On the bright side, sedentary older adults who had low-salt consumption did not show cognitive decline over the three years. And those who had higher levels of physical activity did not show any association between salt and cognition.

Low sodium intake is associated with reduced blood pressure and risk of heart disease, adding even more weight to the mantra: what’s good for the heart is good for the brain.

The analysis controlled for age, sex, education, waist circumference, diabetes, and dietary intakes. Salt intake was based on a food frequency questionnaire. Low sodium intake was defined as not exceeding 2,263 mg/day; mid sodium intake 3,090 mg/day; and high sodium intake 3,091 and greater mg/day. A third of the participants fell into each group. Physical activity was also measured by a self-reported questionnaire (Physical Activity Scale for the Elderly). Cognitive function was measured by the Modified MMSE.

And adding to the evidence that exercise is good for you (not that we really need any more!), a rat study has found that aging rats that ran just over half a kilometer each week were protected against long-term memory loss that can happen suddenly following bacterial infection.

Previous research found that older rats experienced memory loss following E. coli infection, but young adult rats did not. In the older animals, microglia (the brain’s immune cells) were more sensitive to infection, releasing greater quantities of inflammatory molecules called cytokines in the hippocampus. This exaggerated response brought about impairments in synaptic plasticity (the neural changes that underlie learning) and reductions in BDNF.

In this study, the rats were given unlimited access to running wheels. Although the old rats only ran an average of 0.43 miles per week (50 times less distance than the young rats), they performed better on a memory test than rats who only had access to a locked exercise wheel. Moreover, the runners performed as well on the memory test as rats that were not exposed to E. coli.

The researchers are now planning to examine the role that stress hormones may play in sensitizing microglia, and whether physical exercise slows these hormones in older rats.

Data from the Women's Health Initiative Memory Study, involving 6,467 postmenopausal women (65+) who reported some level of caffeine consumption, has found that those who consumed above average amounts of coffee had a lower risk of developing dementia.

Our bodies’ ability to regulate its temperature gets worse with age, along with a slowing metabolism. We also become more vulnerable to Alzheimer's as we age. A study compared mice genetically engineered to manifest Alzheimer's symptoms as they age with normal mice.

People with Alzheimer's disease develop problems in recognizing familiar faces. It has been thought that this is just part of their general impairment, but a new study indicates that a specific, face-related impairment develops early in the disease.

A study involving 100 older adults (aged 80-99) with hearing loss has found that those who used a hearing aid performed significantly better on a cognitive test (MMSE) than those who didn't use a hearing aid, despite having poorer hearing.

A study involving 65 older adults (average age 66), of whom 35 had type 2 diabetes, has found that after two years, those with diabetes had decreases in their ability to regulate blood flow in the brain, and a reduced ability to regulate blood flow was associated with lower cognitive scores.

A small study that fitted 29 young adults (18-31) and 31 older adults (55-82) with a device that recorded steps taken and the vigor and speed with which they were made, has found that those older adults with a higher step rate performed better on memory tasks than those who were more sedentary.